Degenerate code: Difference between revisions
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[[Amino acids|Amino acids]] are [[Transcription|transcribed]] and [[Translation|translated]] from [[DNA|DNA]] molecules consist of [[Nucleotide|nucleotides]]. There are 4 kind of nucleotides (namely [[Adenine| | [[Amino acids|Amino acids]] are [[Transcription|transcribed]] and [[Translation|translated]] from [[DNA|DNA]] molecules consist of [[Nucleotide|nucleotides]]. There are 4 kind of [[Nucleotides|nucleotides]] (namely [[Adenine|adenine]], [[Cytosine|cytosine]] [[Guanine|guanine]] and [[Thymine|thymine]]), however, there are 20 kinds of [[amino acid|amino acid]] so each [[Nucleotide|nucleotide]] cannot correspond directly to each [[amino acid|amino acid]].<br> | ||
In fact, nucleotides are read in groups of 3 called [[Codon|codons]]. Nevertheless, this creates more codons than needed as now the possible combinations is 4<sup>3</sup>=64. | In fact, [[Nucleotide|nucleotides]] are read in groups of 3 called [[Codon|codons]]. Nevertheless, this creates more [[Codon|codons]] than needed as now the possible combinations is 4<sup>3 </sup>= 64.<ref name="Molecular Biology of the Cell">Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K. and Walter, P. (2008) 'Molecular Biology of the Cell', in 5th edGarland Science, pp. 367</ref> | ||
Therefore, solve this problem, the genetic code uses a [http://image.wistatutor.com/content/feed/u496/many%20to%20one%20function.JPG many-to-one] mapping for most amino acids, with the exception for [[Methionine|Met]] and Trp which respectively correspond to a codon. This means the genetic code is [[ | Therefore, solve this problem, the genetic code uses a [http://image.wistatutor.com/content/feed/u496/many%20to%20one%20function.JPG many-to-one] mapping for most amino acids, with the exception for [[Methionine|Met]] and [[Trp|Trp]] which respectively correspond to a [[Codon|codon]]. This means the genetic code is [[Degenerate code|degenerate]].<br> | ||
=== Reference === | |||
<references /> | |||
Revision as of 13:50, 10 January 2011
Amino acids are transcribed and translated from DNA molecules consist of nucleotides. There are 4 kind of nucleotides (namely adenine, cytosine guanine and thymine), however, there are 20 kinds of amino acid so each nucleotide cannot correspond directly to each amino acid.
In fact, nucleotides are read in groups of 3 called codons. Nevertheless, this creates more codons than needed as now the possible combinations is 43 = 64.[1]
Therefore, solve this problem, the genetic code uses a many-to-one mapping for most amino acids, with the exception for Met and Trp which respectively correspond to a codon. This means the genetic code is degenerate.
Reference
- ↑ Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K. and Walter, P. (2008) 'Molecular Biology of the Cell', in 5th edGarland Science, pp. 367